A page of events. Returned with an empty events array
when the supplied opportunity ID does not exist for the
authenticated vendor.

The request was malformed or failed validation. Common triggers
include missing required fields, invalid enum values, type
mismatches, an unrecognized tackle-operation-id, and (for
create) qualificationInfo.legalLanguageAccepted not being
true. The response message describes the specific
violation.

Missing or invalid authentication.

The caller is not authorized to perform this action.

An unexpected error occurred while processing the request.
Retry idempotent reads after a short delay; for writes, check
the opportunity history (GET /api/opportunities/{id}/events)
before retrying to confirm whether the prior request was
applied.